BCSES Informe resumido

The overall objective of BSCES is to quantify the contribution biocrusts (i.e., soil lichens, bryophytes, and other microbial organisms) to ecosystem services in drylands. Our target organisms are widely distributed in drylands, and their functional traits (i.e., morphological, anatomical, physiological, and chemical attributes) exert critical effects on ecosystem processes. Thus, there is a need to include biocrusts as ecosystem services providers in drylands. The understanding of how much biocrusts contribute to ecosystem services will have highly relevant implications on ecosystem management, environmental policy, decision making, and prediction of global change scenarios in drylands. In particular, we expect that BCSES will contribute to protect and restore biocrusts communities and related functions, and thus, to preserve the ecosystem services they provide in areas where natural resources are very scarce. To address the general objective of the project, we proposed the following objectives: O1. To test the effects of biocrust functional traits on ecosystem processes - functional unit level: select and measure biocrust functional traits to investigate their effects on related ecosystem processes at the functional unit level. The selected traits allow a relatively easy, inexpensive and systematic measurement, in order to be practical and repeatable. Since functional groups are not species dependent, this methodology has universal character and can be tested, and then applied worldwide.O2. To investigate the effects of environmental factors controlling the composition of biocrusts, both at the local and regional scale - community level objective: construct a model to predict the proportion of biocrust components from climatic and soil physico-chemical variables. O3. To evaluate the contribution of biocrusts to ecosystem structure in drylands - ecosystem level objective: construct a model to predict biocrust abundance in drylands considering large scale environmental variables. This model would allow us to quantify the relative contribution of biocrusts to ecosystem services, compared to other ecosystem components (i.e., vascular plants), at a regional scale.O4. To quantify the contribution of biocrusts to ecosystem services delivery in drylands: use the results from O1, O2, and O3 to quantify biocrust ecosystem services provision in drylands at three different levels: i) functional unit, ii) community, and iii) ecosystem. This model would be enormously useful to complete the traditional models restricted to vascular plants and to predict changes in biocrust ecosystem services under different global change scenarios.

To achieve the objectives of the project, BCSES has carried out intensive and extensive field and laboratory work, together with advanced statistical analyses, which has produced high quality results:

- From the ecosystem level to the functional unit level, BCSES has characterized biocrust abundance and functional identity across wide environmental gradients, such as climatic and disturbance-recovery gradients in drylands worldwide (from southwestern USA to Portugal and Italy in the Mediterranean region).- BCSES has proposed an integrative and novel approach to quantify biocrust contribution to ecosystem structure by taking into account the vascular plant community and biocrust communities simultaneously.- By gathering biocrust and vascular plant data from wide environmental gradients, BCSES allowed the identification of a general pattern that shows a dominance of the biocrust component in regions with high to medium levels of aridity (e.g., aridity index<0.40), whereas after medium levels of aridity, vascular plants dominated.- A wide variety of biocrust functional groups has been identify at different levels: i) cyanobacteria-lichen-moss level; e.g., notable differences were found in the C and N content in mosses vs. lichens, which has potential implications to nutrient cycling, and ii) within moss and lichen groups; e.g., morphology not only determine differential water absorption and retention capacity for mosses and lichens but also their influence on topsoil humidity and temperature.- The evaluation of environmental factors such as climate and soil properties on biocrusts allowed BCSES to identify those variables that shape these communities and their functional traits, such as annual precipitation and aridity, temperature range and seasonality together with soil phosphorus content, pH and texture.- BCSES research has led into a big data base of biocrust functional traits, where more than 80 species have been classified in terms of morphology, continuity, size, and chemical compounds among others. Functional diversity indices behave differently than traditional taxonomical indices, responding in a particular fashion to environmental variables such as climate and soil properties.- From the global perspective that BCSES provide, it has been shown the relevance of biocrusts in dryland’s diversity and function. Biocrusts are quite abundant in the most arid areas, comprising a wide range of functional traits simultaneously responding to the environmental and influencing soil structure and processes.

The results obtained with BCSES have been and will be published and divulgated both at the academic, scientific and general public level. The knowledge generated during the development of BCSES are very interesting from the point of view of Community Ecology, Functional Ecology and Applied Ecology, since a global assessment of biocrust communities has been conducted in terms of biocrust abundance, taxonomic and functional diversity and contribution to ecosystem services in a wide range of drylands (e.g., grasslands, shrublands, dune systems) and along different environmental gradients (e.g., climatic, disturbance-recovery given by grazing). This information are crucial to rise attention to these complex communities in Ecological Research nowadays. Furthermore, BCSES identified key functional traits tightly related to ecosystem processes which have a notable influence on ecosystem services. Thus, functional diversity of biocrusts provide very useful information as ecological indicators but also in land use management and ecosystem services trade-offs assessment. As part of the divulgation activity of the project, this information has been and will be communicated to different groups of interests, from the scientific community to the private sector and the general public in conferences and meetings.